Snap-acting device



April 8, 1941. KOHL 2.237.705

SNAP -ACTING DEVI CE Filed June 21, 1938 2 Sheets-Sheet l lMS'ULAT/UIV I INSULATION FIG. "4

INSULATION 26 INVENTOR 3 Y EVERARD F. ,KOHL

WMW

ATTO R N EYS April 8, 1941. F, KOHL SNAP-ACTING DEVICE Filed June 21, 1938 2 Sheets-Sheet 2 FIG-7 FIG-9 INSULATION INVENTOR EVERARD F. KOHL FIG.

FIG-l0 ATTORNEYS FIG-I2 Patented Apr. 8, 1941 UNITED STATES PATENT OFFICE 2,231,705 SNAP-ACTING nsvrca Everard F. Kohl, Cleveland, Ohio Application June 21, 1938, Serial No. z14,92s

(Cl. zoo-s1) 11 Claims.

My invention relates to devices in which a member to be actuated may be moved with a snap action for any desirable'purpose. More particulariy, it relates to electrical switches of the snapacting type.

Snap-acting devices which have heretofore been constructed for use in apparatus such as switches, valves, thermostats, relays, and the like, are either somewhat complicated in structure or are lacking in the sensitivity which is required in certain apparatus of this type. It is the aim of the present invention to provide an improved snap-acting device that may be utilized in various apparatus and which is sensitive in operation, economical to manufacture, and has a comparatively long life in service.

Another object of my invention is to provide an improved snap-acting device that is composed of parts which may be assembled in compact and simple form, that may be actuated by a comparatively small movement of an operating force, and which, if desired, may be constructed in such a manner-that it may be inserted'in small places, such as tubes and the like.

A further object or my invention is to provide an improved thermally controlled snap-acting switch which is simple in construction and sensitive in operation, and which has a comparatively long life in service.

Further objects and advantages of my invention will be apparent as the description proceeds.

My invention will be better understood by reference to the accompanying drawings, in which Fig. 1 is a side elevational view of one form of my improved switch;

Fig. 2 is a view similar to Fig. 1 but showing the movable parts in a different position;

Fig. 3 is a front elevational view 01 the switch shown in Fig. 2% it appears when viewed from the right of that figure;

Fig.- 4 is a side elevational view of a modified form of a switch;

Fig. 5 is a side elevational view of a further modification of my improved switch;

Fig. 6 is an-enlarged' cross" sectional view on the line 68 of Fig. 3, with the parts in the position shown in Fig. 1;

Fig. '7 is a view similar to Fig. 6, showing the position of the parts when the operating lever is in its critical position;

Fig. 8 is a view similar 'to'Figs. 6 and 7, showin the position of the parts when the operating lever is moved beyond its critical position;

Fig. 9 is a-side'elevational view 0! a relay showing another form of my improved switch;

Fig. 10 is a sectional plan view of the switch ilglistrated in Fig. 9, taken on the line Ill-J0 of Fig. 11 is a plan view of a thermostat showing a still further form 01' my improved switch;

Fig. 11a is an enlarged cross sectional view on the lines Ila-Ma of Fig. 11; and

Fig. 12 is a side elevational view of the stat shown in Fig. 11.

While my improved snap-acting device may be utilized for any suitable purpose such as operating valves or switches of any desirable type, for purposes of illustration it is shown in the drawings as being utilized in connection with switches for use in various apparatus, such as relays and thermostats.

In Figs. 1 to 3 of the drawings, a snap-acting switch is shown which is adapted to be utilized in electrical devices. As illustrated, the switch includes a member i to be actuated, provided with a tongue 2, and an actuating member'or lever 3 provided with a handle 4 and a tongue 5. As shown, the actuating member is provided with an opening 3a through which the member I to be actuated may be moved. While the member to be actuated and the actuating member may be formed integrally or supported in any desirable manner, as shown in Figs. 1 to 3 of the drawings, both members are made of flexible metal and are arranged with the stationary end of the actuating member adjacent to the stationary end of the member to be actuated, these adjacent ends being secured together by a suitable base structure designated generally by the numeral 6.

A suitable spring I is operatively associated with the actuating member and the member to be actuated. As illustrated, the spring consists of a thin flat piece of resilient metal, such as Swedish steel, beryllium copper, brass or the like, and is provided with apertures spaced a short distance from its opposite ends to receive tongues 2 and 5 when the strip is compressed into substantially the shape of a half circle.

In preparing the spring, a metal strip of the desired width is rolled to a predetermined thickness and heat treated to give it the desired temper. Apertures are then punched in the strip at the desired distance apart in accordance with the length of spring desired and the metal strip is then cut to provide a spring of the proper length. Springs of the same length and sensitivity may therefore be readily prepared in a commercial manner so that switches or other devices in which they are employed may be duthermois moved with a rolling action until the actuating lever reaches a Point at which the apertures 1c and Id in spring l are substantially in alignment with the free end of member I, and the ends 1a and lb of spring I are substantially at right angles to member i. At this point actuating member 3 is in its critical position and tongues 2 and 5 fit loosely in slots 1c and lid.

'Upon further movement of actuating member 3 in the same direction, as illustrated in Fig. 3, spring 1 engages member i with a thrust action and throws it with a snap action in the opposite direction. It will be noted that after the fiat spring is compressed into shape for assembly, the compression of the spring during actuation is substantially negligible and consequently the spring will retain its sensitivity. It will also be apparent that because of the rolling action imparted to the spring during actuation and because of the thrust action of the entire width of the spring against the member to be actuated after the actuating member has passed its critical position, the wear upon the spring is small, and it will therefore have a long life in service. Consequently, the spring may be made from comparatively thin strips or metal, thereby increasing its sensitivity.

The movable parts are now in the position shown in Fig. 2 of the drawings. Upon moving lever 3 in the direction indicated by the arrow B in Fig. 2, spring 7 will be moved with a rolling action until the lever 3 reaches a critical position and the apertures in spring I are substantially in alignment with the free end of member 8, and upon further movement of the lever in thesame direction, member i will be returned with a snap action to the position shown in Fig. 1.

' In the switch shown in Figs. 1 to 3, inclusive,

of the drawings, the flexible member i which is formed of a suitable electrically conductive metal, such as copper or brass, is provided with a contact 9 on one face thereof which is adapted to engage a contact 9 on the inner face oi an arm it secured to the base structure 6 when the movable parts are in the position shown in Fig. l. The flexible member 8 is also provided with a contact ii on its opposite face which is adapted to engage a contact ii on the inner face of an arm 98 secured to the base structure 6 when the parts are in the position shown in Fig. 2 of the drawings. Arms it and i8 are formed of electrically conductive metal, or if a single-throw switch is desired, either the arm in or 93 may be utilized as a stop.

While the base structure 6 may be or any suitable form for securing the stationary ends of arms i0 and i3 and members i and 3 in place and maintaining arms is and is in spaced electrically insulated relationship, as shown the parts are held together by means of bolts id which pass through apertures in the adjacent ends of the arms and members and through insulating strips 95, such as fiber or molded material, interp'osed between the heads of bolts l4 and arm it, between arms to and 93, respectively, and members i and 3 and between arm lb and nuts it by means of which the bolts are held in place. The metallic members are also insulated from the bolts by any suitable means, such as tubes its. To provide terminals H, is and l9, a portion or arm i0, operating lever 3 and arm 13 extend beyond the base structure 8. While in the structure shown, operating member 3 is extended to form terminal i 8 because it is formed of thicker metal than member 8 and the adiacent end of members i and 3 are held together by the bolts in electrical contact with each other, terminal 58 may be formed upon the member 6 and must be formed upon that member it the stationary ends of members I and 3 are electrically insulated from each other.

In the form of switch shown in Figs. 1 to 3, inclusive, it will be noted that when the flat spring member i is assembled in place, it is compressed to a considerable extent. It therefore requires only a short actuation oi lever 3 in the direction indicated by arrow A or arrow B as shown in Figs. 1 and 2 of the drawings to move it to its critical position. Upon movement of the operating lever past the critical position, the thrust action of the spring. throws member i with a snap action in the opposite direction causing contact Ii to engage contact l2 when the movement of the actuating member is in the direction indicated by the letter A, or causing contact 8 to engage contact 9 when the movement of the actuating member is in the direction indicated by the letter B. After member I has been actuated, the spring retains suflicient compressive force to maintain contacts 8 and 9 or contacts ii and E2 in firm engagement with each other and this engagement is maintained until the actuating lever is again moved beyond the critical plane. A quick make and break-oi. the contacts is therefore provided which minimizes volatilization of the contacts. It will also be noted that when the contacts are made it is not necessary for current to flow through the spring 8 which may therefore be formed of metal,

- such as steel, which has less electrical conductivity than members i and arms l0 and I3.

The switch shown in Fig. 4 is somewhat similar to that shown in Figs. 1 and 3, inclusive, and spring l is associated with the member to be actuated and the actuating member in the same manner. In this form of switch, however, two additional flexible metallic arms 2!! and iii are secured to the base structure 6, arm 20 being interposed between, and its stationary end being electrically insulated from arm i0 and member 8, and arm 2! being interposed between, and its stationary end being electrically insulated from arm l8 and actuating lever 3. Arm 2c is provided on one race with a contact 22 which is adapted to engage contact 9. and with a contact 28 on its opposite face which is adapted to engage contact 8 when members i and 3 are in the position shown in Fig. 4 of the drawings, and arm 2i is provided on one face with a contact 25 with which contact ii is adapted to engage, and with a contact 25 which is adapted to engage contact i2 when actuating lever B is moved in the direction indicated by the arrow C beyond the critical plane to a position similar to that shown in Fig. 2 of th drawings. A portion of arms 2@ and 2! are extended beyond base structure 6 to form terminals 28 and 27.

Another form of switch is shown in Fig. 5 of the drawings in which the actuating member 3 and the member 6 to be actuated are formed of flexible conductive metal strips insulated from each other. This switch is somewhat similar to that shown in Figs. 1 to 4, inclusive, and the same numerals have been applied to the elements in the drawings. As illustrated, the member to be actuated is provided with contacts 6 and I I for engagement with contacts 9 and I2 on the inner face of metallic arms I and I3, the opposite ends of members I and 3 and the arms I0 and I9 being secured together by bolts I4 and spaced from each other by insulating strips I5.

In this form of structure, the movement of actuating member 3 in the direction indicated by the arrow F throws member I in the opposite direction, forcing contact II with a snap action into engagement with contact I2. Upon release of the force upon operating member 9, spring 1 forces member I to the position shown in Fig. 5, causing contact 6 to engage contact 9. This action may be effected either by arranging member 3 in closer relationship to arm I3 than to arm I0, or by forming the member 3 of stronger material than spring 1 and biasing it toward arm I9.

Another modified form of my improved device is shown in Figs. 9 and 10 of the drawings, which also illustrates its use in a relay. As shown in the drawings, a suitable frame 56 supports an electromagnet 51 and is provided with a pair of arms 58 and 59 extending outwardly from one side on which contacts 60 and 6 I, respectively, are supported. An actuating lever 62 formed of conductive metal is pivotally mounted upon the opposite side of the frame, the pivoted end being in conductive engagement with a contact 63 secured to the frame. While any suitable means may be provided for pivotally mounting operating lever 62 on frame 56, as shown in the drawings the end 64 of lever 62 projects loosely through an elongated slot in the frame and is provided with an opening 65 to receive one end of contact 63, the end 64 of lever 62 being provided with a tongue 66 which extends loosely through openings in the contact and the from The free end of lever 62 may therefore be oscillated through a predetermined arc.

K A member 61 to be actuated which is formed of conductive metal and provided with contacts 68 and 69 is pivotally mounted upon operating lever 62 in any convenient manner. As illustrated, one end of member 61 has a downwardly extending flange 10 provided with an aperture to loosely receive a tongue 1I formed upon a cross bar 12. Operating lever 62 is also provided with an opening 65a through which one end of member 61 extends and with a cross bar 13 provided with a tongue 14 which extends through an aperture in one end of a flat spring 15, the other end of spring 15 being provided with an aperture to receive a tongue 16 on member 61. The end piece 16a of lever 62 is also provided with a tongue 11 which extends through an aperture in one end of a flat spring 18, the other end of spring 119 being provided with an aperture to receive a tongue 19 secured to arm 59. I

As illustrated in the drawings, member 61 is held in such position by spring 15 that under normal conditions contact 69 is in engagement with contact SI and actuating lever 62 is held against a downwardly extending flange 60 on arm 58 by the force of compressed spring 16. When electromagnet 51 is energized, however, lever 62 is forced downwardly, causing a rolling movement of spring 18 and also causing a rolling movement of spring 15 until lever 62 reaches a critical position, and upon further movement,

spring 15 throws the free end of lever 61 upwardly causing contact 68 to engage contact 60 with a snap action. When electromagnet 61 is de-energized spring 16 forces actuating lever 62 upwardly until it abuts flange 60, moving spring 16 with a rolling action until actuating lever 61 passes its critical position, whereupon spring 15 forces lever 61 downwardly with a snap action causing contact 69 to engage contact 6i.

Another modification of my improved switch is shown in Figs. 11 and 12 of the drawings. In this form of switch the end of the coil portion of a bimetallic member 96 is held in the groove of a post 99 by means of a screw I00 and the free end I02 of the bimetallic member extends between contacts I03 and I04 which are supported by a movable arm I05 pivotally mounted upon the base by any suitable means, such as a screw I06. Contacts I03 and I04 are connected with suitable terminals by means of conductors I01 and I08. The end portion I02 of the bimetallic member is provided with an opening I09 forming an end piece II 0 from which a tongue III extends. A tongue I I2 formed on the bimetallic element also extends into the opposite edge of the opening and passes through an aperture in a flange of a flexible arm II3, the other end of the flexible arm being provided with a tongue I I4 extending through apertures in the end portions of a flat spring II5 formed of resilient metal, such as steel or one of the other metals specified, which as shown is bent into a substantially circular form, the middle portion of the spring II6 being provided with an aperture through which tongue III extends. It will be understood that when the end portion I02 of the bimetallic member is in its critical position the tongues fit loosely in the apertures in the spring.

In a thermostat of this construction, opposite forces are applied upon bimetallic member 99, as is well known in the art, by variations in the temperature. For instance, when the bimetallic member is heated a force may be applied upon the'bimetallic member as indicated by the arrow I, which causes a rolling movement of spring I I5 until the end member reaches a critical position, whereupon spring II5 throws arm II3 with a snap action in the opposite direction causing contact 3a on member II3 to engage contact I04, whereas when force is applied to bimetallic member 99 in the direction as indicated by the arrow J, such as a force that may be caused by cooling of the bimetallic member, spring H5 is moved with a rolling action until the bimetallic member reaches a critical position, whereupon spring II5 throws arm II3 with a snap action in the opposite direction causing contact II3b to engage contact I03. As illustrated in the drawings, force has just been applied in the direction indicated by the arrow J.

As illustrated, means are also provided for varying the position of the electrodes, and thus varying the force required on the bimetallic member to move its end portion I02 to the critical position. As shown in Fig. 11, electrodes I03 and I04 are mounted upon a movable member I05, and a cam member I23 provided with a handle I24 is utilized for varying the distance of electrodes I03 and I04 from the free end I02 of the bimetallic member 96. In this construction, when handle I24 is moved to the left, electrode I03 is displaced further to the left as shown in Fig. 11 of the drawings. Upon such movement, the force required to throw the end portion I02 of the bimetallic member in the direction indicated by arrow I to cause spring II5 to throw arm H3 to the right, is therefore intallic member 98 in the direction of the arrow J will be required to cause spring M5 to throw arm i iii to the left. Upon moving handle I24 to the right the opposite effect will be obtained as will be readily understood.

In the thermostat disclosed it will be noted that the end portion H32 of the bimetallic element extends between electrodes m3 and 80%. The thermostat will therefore be sensitive in operation. In view of the rolling movement of the spring H5 and the fact that its compression during actuation is substantially negligible, the thermostat retains its sensitivity over a comparatively long period. The fact that the spring is not preformed but is cut from metal strips also enables instruments to be constructed which are uniform and which do not require adjustment in service.

What I claim is:

l. A device of the character described, com= prising an actuating member and a member to be actuated, each having a free end, a support formed integral with the free end of each memher which is spaced from the support of the other member, an arcuate-shaped spring interposed between and having portions bearing upon said supports and said supports being in suficiently close proximity to each other to hold said spring under compression, and means for maintaining said spring in operative association with said members and for rocking it upon said supports, said means including an integral projection on said actuating member loosely interconnected with a portion of said spring which is adapted to engage said spring and move it bodily with a rocking action on said supports during movement of said actuating member and an integral projection on the member to be actuated having a lost motion connection with another portion of said spring which permits reciting movement of said spring upon the support of the member to be actuated.

2. A device of the character described, comprising an actuating member and a member to be actuated, each having a free end and the free end of each member having a flat support which is spaced from the support of the other member, a normally flat spring interposed between and having smooth portions resting upon said supports and said supports being in sufiiciently close proximity to each other to hold said spring under compression with portions thereof in the form of an arc, and means for maintaining said spring in operative association with said members and for rocking it upon its supports, said means including a projection upon said actuating member loosely interconnected with a portion of said spring which is adapted to engage said spring and move it bodily upon said supports with a rocking action during movement of said actuating member, and a projection upon the member to be actuated having a lost motion connection with another portion of said spring which permits a rocking movement of said spring upon the support of the member to be actuated.

3. A device of the character described, comprising an actuating member and a member to be actuated, each having a free end movable in an arc and the free end of each member having a fiat support which is spaced from the support of the other member, a normally flat spring interposed between and having smooth portions insumciently close proximity to each other to hold said spring under suflicient compression with portions thereof in the form of an arc to maintain the free ends of said members at the opposite ends of their arcs with portions of the spring bearing against the inner edges of both supports, and means for maintaining said spring in operative association with said members and for rocking it upon said supports, said means including a projection upon said actuating member extending beyond its support and loosely interconnected with a portion of said spring and a projection upon the member to be actuated .having a lost motion connection with another portion of said spring, the movement of said actuating member from one end of its arc to the other being adapted to force the projection upon the actuating member into engagement with said spring and move it bodily with a progressive rocking action of portions thereof upon said supports until the spring engages the outer edge of the support of the member to be actuated and throws it with a snap action in a direction opposite to the movement or the actuating member.

4. A device of the character'described, comprising an actuating member having a free end movable in an arc to and beyond a critical position, a member to be actuated having a free end movable in an arc, each of said members ha ing a fiat support which is spaced from the support of the other member, a normally flat spring interposed between and having smooth portions bearing upon said supports, said supports being in sufilciently close proximity to each other to hold said spring under sufilcient compression with portions thereof in the form of an arc to maintain the free ends of said members at the opposite ends of their arcs with a portion of the spring bearing against the inner edges of each support, and means for maintaining said spring in operative association with said members and rocking it upon said supports, said means including a projection upon said actuating member extending beyond its support and loosely interconnected with a portion of said spring and a projection upon the member to be actuated having a lost motion connection with another portion of said spring, the movement of said actuating member to its critical position being adapted to force the projection upon the actuating member into engagement with said spring and move it bodily with a progressive rocking action upon said supports without moving the member to be actuated, and the movement of said actuating member beyond its critical position being adapted to cause a portion of said spring to engage the outer edge of the support of the memberto be actuated and force it with a snap action in a direction opposite to the movement of the actuating member.

5. A device of the character described, comprising an actuating member and a member to be actuated. each having a free end movable in an arc and the free end of each of said members being provided with a tongue and substantially fiat shoulders on opposite sides of said tongue, the tongue and shoulders on one member being in spaced relation to the tongue and shoulders on the other member, a normally fiat spring having spaced apertures therein, one of which is adapted to loosely receive one of said tongues and the other oi. which is adapted to loosely receive the tongue of the other member when said bearing upon said supports, said supports being spring is compressed with portions thereof in the form of an are, said tongues being of sufllcient length to maintain said members in operative association with said spring, the apertures in said spring being of suillcient size to permit rocking movement of said spring upon said shoulders and said spring being under sufflcient compression to maintain said members at the opposite ends of their arcs with portions of the spring bearing against the inner edges of the shoulders of both members, the movement of said actuating member in its are being adapted to force its tongue into engagement with said spring and bodily move it with a progressive rocking action on said shoulders until a portion of said spring engages the outer edge of the shoulder of the member to be actuated and throws it with a snap action in a direction opposite to the movement of the actuating member.

6. A device of the character described, comprising an actuating member having a free end movable in an arc to and beyond a critical position, a member to be actuated having a free end movable in an arc, the free end of each of said members being provided with a tongue and substantially flat shoulders on opposite sides of said tongue, the shoulders on one member being spaced from the shoulders on the other member and being substantially opposite thereof when the actuating member is in its critical position, a normally flat spring having spaced apertures therein, one of which is adapted to loosely receive the tongue of one member and the other of which is adapted to loosely receive the tongue of the other member when said spring is compressed with portions thereof in the form of an arc, said tongues being of sufficient length to maintain said members in operative association with said spring and the spring being under sufficient compression to maintain said members at the opposite ends of their arcs with portions of the spring bearing against the inner edges of the shoulders of both members, the movement of said actuating member to its critical position being adapted to force its tongue into engagement with said spring and bodily move it with a rocking action on said shoulders without effecting movement of the member to be actuated, and the movement of the actuating member beyond its critical position being adapted to rock the spring sufficiently to cause a portion of the spring to engage the outer shoulder of the member to be actuated and throw it with a snap action in a direction opposite to the movement of the ac-' tuating member.

7. A device of the character described, comprising an actuating member having a free end movable in an arc to and beyond a critical position, a member to be actuated having a free end movable in an arc, the free end of each of said members being provided with a tongue and substantially flat shoulders on opposite sides of said tongues, the shoulders on one member being spaced from the shoulders on the other member and being substantially opposite thereof when the actuating member is in its critical position, a normally fiat spring having apertures adjacent the opposite ends thereof, one of which is adapted to loosely receive one of said tongues and the other of which is adapted to loosely receive the tongue of the other member when said spring is compressed with portions thereof in the form of an arc, said tongues being of suflicient length to maintain said members in operative association with said spring and the apertures in said spring being of sufficient size to permit rocking movement of said spring upon said shoulders, and said spring being under suilicient compression to maintain said members at the opposite ends of their arcs with portions of the spring bearing against the inner edges of the shoulders of both members, the movement of said actuating member to its critical position being adapted to force its tongue into engagement with said spring and bodily move it with a rocking action on said shoulders without effecting movement of the member to be actuated, and the movement of the actuating member beyond its critical position being adapted to rock the spring sufficiently to cause a portion of the spring to engage the outer shoulder of the member to be actuated and throw it with a snap action in a direction opposite to the movement of the actuating member.

8. A snap acting switch comprising a lever fixed at one end and having a free end movable in an arc, an arm having a fixed end and a free end movable in an arc with contacts arranged on opposite sides thereof, fixed contacts arranged opposite to the contacts on said arm, the free end of said lever and the free end of said arm each being provided with a tongue having fiat shoulders on opposite sides thereof and the shoulders on said lever being spaced from the shoulders on said arm, a normally flat spring having spaced apertures therein, one of which loosely receives the tongue on said lever and the other of which loosely receives the tongue on said arm when said spring is compressed with portions thereof in the form of an arc, said tongues being of suflicient length to maintain said lever and arm in operative association with the spring, said apertures being of sufiicient size to permit rocking action of the spring upon said shoulders, and said spring being under sufficient compression to maintain said lever at one end of its arc with one portion of the spring bearing against the inner edge of the shoulders on said lever and another portion of the spring bearing against the inner edge of the shoulders on said arm, thereby maintaining the contactor on one side of the arm in engagement with one of the fixed contacts, the movement of said lever through its are being adapted to force its tongue into engagement with said spring and move it bodily with a progressive rocking action on said shoulders until a portion of said spring engages the outer edge of the shoulder on said arm and throws it with a snap action ina direction opposite to the movement of the actuating member, thereby causing the contact on the opposite side of the arm to engage the other fixed contact.

9. A snap acting switch comprising a slotted lever fixed at one end and having a free end movable in an arc to and beyond a critical position, the free end of said lever being provided with a tongue and substantially flat shoulders on opposite sides thereof, an arm having a fixed end and a free end movable in said slot and being provided with contacts on opposite faces adjacent its free end, the free end of said arm being also provided with a tongue and substantially flat shoulders which are spaced from the shoulders on said lever, a normally fiat spring having apertures adjacent the opposite ends thereof, one of which loosely receives the tongue on said lever and the other of which loosely receives the tongue on said arm when said spring is compressed with portions thereof in the form of an arc, said tongues being of suflicient length to maintain said lever at one end of its arc with one portion of the spring bearing against the inner edge of the shoulder on said lever and another portion of said spring bearing against the inner edge of the shoulder on said arm, thereby maintaining the contact on one side of the arm in engagelever beyond its critical position beingadapted' to cause a portion of said spring to engage the opposite edge of the shoulder on said arm and throw said arm with a snap action in a direction opposite to the movement of the actuating member, thereby causing the contact on the opposite face of the arm to engage the other fixed contact.

10. A device of the character described, comprising an actuating member and a member to be actuated, each having a free end and the free end of each member having a, support which is spaced from the support of the other member, an arcuate-shaped spring interposed between and having a portion at one end of its are bearing on one of said supports and a portion at the other end of its are bearing on the other support and said supports being in sufdciently close proximity to each other to hold said spring under compression, and means for maintaining said spring in operative association with said members and for rocking it upon said supports, said means including a projection on said actuating member loosely interconnected with a portion of said spring which is adapted to engage said spring and move it bodily with a rocking action on said supports during movement of said actuating member and a projection onthe member to be actuated. having a lost motion connection with another portion of said spring which permits rocking movement of said spring upon the support of the member to be actuated.

11. A device of the character described, comprising an actuating member and a member to be actuated, each having a free end and the free end of each member having asupport which is spaced from the support of the other member, a normally flat spring interposed between and having smooth portions resting upon said supports and said supports being in sumciently close proximity to each other to hold said spring under compression with portions thereof in the form of an arc, and means for maintaining said spring in operative association with said members and for rocking it upon its supports, said means including a projection upon said actuating member loosely interconnected with a portion of said spring which is adapted to engage said spring and move it bodily upon said supports with a rocking action during movement of said actuating member, and a projection upon the member to be actuated-having a lost motion connection with another portion oi said spring which permits a rocking movement of said spring upon the support of the member to be actuated.

EVERARD F. KOHL. 

